Reduction of graphene oxide at the interface between a Ni layer and a SiO₂ substrate

Reduction of graphene oxide (GO) was carried out on SiO₂ using a thin Ni overlayer as a catalyst. A Ni/GO/SiO₂ structure was heated at 800 C in high vacuum for 6 min. After removing the Ni overlayer, formation of graphene was confirmed by Raman spectroscopy. For the Ni overlayer thinner than 40 nm, GO was reduced to graphene on-site. For the thicker Ni overlayer, however, GO was completely decomposed and graphene was formed in a segregation and/or precipitation process. The use of GO with a thin Ni overlayer enabled on-site and transfer-free fabrication of graphene without use of such flammable gases as methane and hydrogen.